1. Field of the Invention:
This invention relates to an apparatus such as a camera which is arranged to automatically perform film winding and rewinding by means of a motor.
2. Description of the Prior Art:
A camera which is arranged to wind and rewind a roll of film with a motor and to automatically rewind the film when the film comes to the end of the roll with a predetermined number of frame portions thereof wound up has been proposed in U.S. Pat. No. 4,400,074. In this camera, the travelling state of the film is detected and, in case that the film travel is interrupted, a rewinding action is carried out with the film considered to have come to the end of the roll. The device for carrying out this operation includes a timer circuit which is set at a very short time for a period of time required for winding each frame portion of film. The timer circuit is arranged to be reset by the rotating action of a rotating body which is responsive to the film travel and not to reach the end of the set time while the film is in transit. When the timer circuit reaches the end of a set length of time, the film rewinding action is permitted to occur with the film considered to have come to its end state thus stopping the rotating body from rotating.
Such an apparatus, however, necessitated provision of an additional member such as the above-stated rotating body for detecting the travelling state of the film. This complicates the structural arrangement and is extremely disadvantageous for an apparatus that must meet a requirement for reduction in size. Further, in the case of an apparatus of this type, the film comes to an end position the instant the timer circuit is reset by the rotating body and, when the travel of the film comes to a stop, the timer circuit remains in a reset state to automatically hinder a rewinding action. Therefore, to solve this problem, it is necessary to use a detection circuit such as a differentiation circuit for detecting that instant. Then, the detection circuit further complicates the structural arrangement.
Further, when a film rewinding action begins in the apparatus of the kind arranged to automatically rewind a roll of film, if the battery which is used as a power source is consumed to such a degree that it is no longer capable of rewinding the whole roll of film, the film would come to a stop before completion of the film rewinding action. In that instance, in the case of an arrangement to electrically control the film rewinding action, the electric circuit provided for that purpose would be reset upon replacement of the consumed battery. As a result of that, the camera or apparatus would be brought into a wound up state to permit no further film rewinding when the battery is replaced with new one. Moreover, contemporary cameras are generally arrranged to automatically come to a stop upon completion of film rewinding. The operator who is accustomed to cameras of this type tends to think that the film has been completely rewound and thus tends to ruin the roll of film by opening the lid of the camera when the film rewinding action comes to a stop halfway under the above-stated condition.